In a large mixing bowl, stir together almond flour, oats, coconut, vegan chocolate chips, baking powder, salt (optional), pumpkin pie spice, and brown sugar.
In a separate bowl, beat aquafaba (using a handheld mixer or by whisking vigorously, though it takes longer) until light and fluffy and loose peaks have formed. (Add a little cream of tartar to help it along if it’s not whipping.)
To the aquafaba, add the pumpkin butter, oil, and vanilla (optional) and beat or whisk to combine. (The mixture will deflate a little — that's okay). Then add to dry ingredients and mix until combined. You should have a firm, semi-tacky dough (see photo). If too wet, add a bit more almond flour or meal. Cover and chill in the refrigerator for at least 30 minutes or overnight.
Preheat oven to 350 degrees F (176 C) and line a baking sheet with parchment paper.
Scoop chilled dough into roughly 2-Tablespoon amounts (I like this scoop) and place onto prepared baking sheet. Press down slightly to form a disc (see photo). Leave about a 1-inch gap in between each cookie to allow for spreading. There should be about 14 cookies (as the original recipe is written). Option to add a few more chocolate chips on top.
Bake for 14-16 minutes or until the edges are slightly golden brown and they’ve expanded. Be careful not to burn (especially on the bottoms) — they bake quickly toward the end.
Remove from oven and let cool for 5 minutes on the baking pan before serving. They will firm up the longer they cool (they can be a bit tender right out of the oven).
Store completely cooled leftovers in a loosely sealed container at room temperature up to 3 days, in the refrigerator for 4 days, or in the freezer for 1 month. On day one they are a bit crisp, but on days 2 and on they are more tender and pillowy (it’s kind of the nature of pumpkin cookies). I recommend storing them in the freezer once cooled to help retain their crispy exterior!